1 General Concepts

Question 1

What are sensitivity, specificity and Baye’s theorem?

Answer 1

Sensitivity = TP / (TP + FN)

Specificity = TN / (TN + FP)

Baye’s theorem considers the pre-test probability, the likelihood of the disease in the population before the test, to estimate if the result is a true result.

Question 2

What are the inpatient and outpatient TTE indications?

Answer 2

…

Question 3

What are the other imaging technologies?

Answer 3

Catheterisation, CT, MRI and nuclear.

Question 4

What are the indications, advantages and disadvantages of the other imaging technologies?

Answer 4

Left heart catheterisation is indicated for the assessment and treatment of CAD. Right heart catheterisation is indicated for the assessment of intracardiac pressures and oxygen levels. The advantages are the high sensitivity and specificity for CAD and the ability to both assess and treat CAD. The disadvantages are its invasiveness and risk of complications, and exposure to contrast and radiation.

CT is indicated for patients with CAD and cardiac disease. In cardiac CT, the scanner includes an X-ray source, and, when the patient moves through the scanner, the scanner creates multiple slices. Using ECG gating, the software processes the slices to create a 3D image. Cardiac CT calculates the coronary calcium score to assess the severity of CAD. The advantages are its high spatial and temporal resolution, ability to create a 3D image and ability to characterise plaque. The disadvantages are its exposure to contrast and radiation and requirement for a slow and regular heart rate.

MRI is indicated for patients with ischemia. In cardiac MRI, radio waves are transmitted to the heart, align with hydrogen nuclei, and are emitted to the scanner with the magnet. The scanner uses the signals to create an image. A stress cardiac MRI is able to assess myocardial ischemia and viability. A contrast MRI (gadolinium) is able to assess myocardial perfusion. The advantages are the quantity of information, ability to create a 3D image and ability to characterise tissues. The disadvantages are exposure to magnetics and contraindications for patients with devices, exposure to contrast, and time and cost.

Nuclear cardiac imaging is indicated for patients with ischemia. Nuclear cardiac imaging uses radioactive isotopes to offer information on myocardial perfusion, viability and function. MPI uses SPECT or PET. The advantages are its high sensitivity and specificity. The disadvantages are the exposure to high levels of ionising radiation and its complexity.